Production of halogenonaphthalenes

ABSTRACT

Halogenonaphthalenes are produced by contacting a naphthalene sulphonyl halide with a sulphuryl halide and a free radical source e.g. a peroxide or hydroperoxide.  The process is stated to be less effective for producing fluoro- and iodothan for chloro- and bromo-naphthalenes. More than one sulphonyl halide group may be attached to the naphthalene nucleus which may also contain other substituents. Specific products mentioned are 1-chloro- and 2-bromo-naphthalenes, 1,5- and 2,7-dichloro- and dibromo-naphthalenes; 1,5-dichloro-3-nitro-naphthalene; 2,7-dichloro-1-methylnaphthalene; 1,5,7-trichloronaphthalene.

l PRGDUCTION OF HIALOGENONAPHTHALENES WilliamCummings;.Marford, Wales, assigiior to Monsanto: Chemicals Limited, London, England, a British company No Drawing.1 Filed Aug. 29,1963, Ser. No. 305,517

Claims pr iority, application Great Britain, Sept. 7, 1962,

34,286/162 Claims. (Cl. 260-650) free from: impurities and in high yields. The process is particularly valuable for the production of isomers that are notreadily accessible by conventional syntheses.

The process of the invention is one for the production bfda halogenonaphthalene, in which a naphthalene sulfonyl. halideis contacted with a sulfuryl halide and a compound which, under the reaction conditions, is a source of free radicals, such that sulfur dioxide is elimif na ted from a sulfonylhalide group of the naphthalene sulfonyl halide, and the halogen atom of the sulfonyl hajlide groupq is introduced into the naphthalene nucleus.

. The. compound that is a source of free radicals is preferably a peroxide such as, for instance, benzoyl per- The quantity of sulfuryl halide employed is generally less than the. molar. equivalent of the sulfonyl halide,

while thecompound that is a source of free radicals is normally requiredfin only a catalytic amount.

Usually thetprocess is conducted at a temperature above lamrbient temperaturebut lower than the temperature at which :the naphthalene sulfonyl halide would itself decompose thermally. A temperature in the range of 30%11500. is often suitable, for instance, in the range of By using the appropriate sulfonyl halide, the required halogenonaphthalene can be produced; for instance, a

naphthalene sulfonyl chloride gives a chloronaphthalene, and a naphthalene; sulfonyl bromide gives a bromonaphthalene. Because of the generally greater stability of the aromatic sulfonyl fluorides, and the ease with which obtained by the use of a mono-, di-, trior other approbe a halogen. atom, for instance fluorine, chlorine or bromine; an aliphatic group, for example an alkyl or cycloalkyl group such as a methyl, ethyl or cyclohexyl group,

or an alkoxy group such as a methoxy or ethoxy group;

an. aromatic group, for example an aryl or aryloxy group, such: as a phenyl, tolyl or phenoxy group; or a nitro group;

Itllis generally desirable that the halogen of the sulfuryl halide he thesame as thehalogen of the sulfonyl halide group ;or groups in the naphthalene sulfonyl halide. For

example sulfuryl chloride is usually employed with a naphthalene sulfonyl chloride, and sulfuryl bromide with a naphthalene sulfonyl bromide.

Patented Jan. 10, 1967 Specific examples of halogenonaphthalenes that can be produced by the process of the invention are l-chloronaphthalene; 2-brom'onaphthalene; 1,5-dichloronaphthalene; 2,7-dichlor-onaphthalene; 1,5-dibromonaphthalene; 2,7-dibromonaphthalene; 1,S-dichloro-3-nitronaphthalene; 2,7-d-ichloro l methylnaphthalene; and 1,5,7-trichloronaphthalene.

Preferably, the process is carried out in the presence of a solvent, especially one that is substantially inert to free radicals under the reaction conditions. Good results are obtained using, for example, halogenated aliphatic hydrocarbons in which all or most of the hydrogen atoms have been replaced'by halogen (e.g., carbon tetra chloride and carbon te-trabromide).

It is usually possible to select a solvent having a boiling point such that the reaction can be carried out at atmospheric pressure. The process can be conducted at an elevated pressure (in the presence or absence of the solvent) should this be necessary.

Usually it is sufiicient to use not more than about 0.3 mol of the sulfuryl halide per mol of the sulfonyl halide (or per sulfonyl halide group where the sulfonyl halide is a polysulfonyl halide), and good results are obtained using, for example, 0.1 or 0.05 mol of sulfuryl halide for each sulfonyl halide group present per mol of the sulfonyl halide.

The compound that is a source of free radicals can, for example, be an azo or diazonium compound, but is preferably a peroxide or hydroperoxide such as hydrogen peroxide, tertiarybutyl hydroperoxide, cumyl hydroperoxide or benzyl peroxide. The last named gives very good results.

The quantity of the compound that is a source of free radicals need not normally exceed about one-tenth of the molar equivalent of the sulfuryl halide, from about onefiftieth to about one-twentieth of the molar equivalent of the sulfuryl halide being usually sufiicient.

The invention is illustrated by the following examples.

Example 1 This example describes the production of 1,5-dichloronaphthalene.

A stirred mixture of 460 grams (1.42 mol) of naphthalene-1,5-disulfonyl chloride, 23 cc. (0.28 mol) of sulfuryl chloride, and 4.6 grams (0.019 mol) of benzoyl peroxide in 2 liters of carbon tetrachloride is heated to boiling under reflux for 6% hours. Sulfur dioxide is evolved. Much of the sulfonyl chloride is present initially as a suspension, but complete solution occurs after 3 hours. The final solution is filtered while hot to remove a small amount of insoluble material, and the carbon tetrachloride is distilled from the filtrate. Crystallization of the residue from ethanol gives 256 grams (92% of the theoretical yield) of 1,5-dichloronaphthalene as colorless crystals having a melting point of 106-108 C.

Example 2 2,7-dichloronaphthalene is obtained as crystals having a melting point of l13116 C. in of the theoretical yield by essentially the same procedure as described in Example 1. The starting materials employed are 476 grams (1.47 mol) of naphthalene-2,7-disulfonyl chloride, 24 cc. (0.3 mol) of sulfuryl chloride and 4.8 grams (0.02 mol) of benzoyl peroxide.

Following the procedure described in Example 1, the following naphthalene sulfonyl halides (a) are employed to yield the halogenonaphthalenes (b) indicated. It will be understood that the appropriate sulfuryl halide is also employed as a starting material.

Example 3 2-chloro-1-naphthalene sulfonyl chloride 1,2-dichloronaphthalene Example 4 8-nitro-1-naphthalene sulfonyl chl-oride 1-chloro-8-nitronaphthalene Example 5 7-methyl-1-naphthalene sulfonyl chloride 1-chloro-7-rnethylnaphthalene Example 6 2-isopropyl-l-naphthalene sulfonyl chloride 1-chloro-2-isopropylnaphthalene W V Example 7 3,7-di-t-butyl-l-naphthalene sulfonyl chloride 1-chloro-3,7-di-t-butylnaphthatlene Example 8 4,5-dinitro-1-naphthalene sulfonyl chloride 1-chloro-4,5-dinitronaiphthalene Example 9 4-chloro-3-nitro-l-naphthalene sulfonyl chloride 1,4-dichloro-3-nitronaphthalene Example 10 4-methoxy-3-methyl-1-naphthallene sulfonyl chloride 1-chloro-4-methoXy-3 -methylnaphthalene Example 11 3,6-dichloro-2-naphthalene sulfonyl chloride 2,3,6-trichloronaphthalene Example 12 4,7-diisopropyl-2-naphthalene sulfonyl chloride 2-chloro-4,7-diisopropylnaphthalene Example 13 6-ethyl-2-naphthalene sulfonyl chloride 2-chloro-6-ethylnaphthalene Example 14 3-methoxy-2-naphthalene sulfonyl chloride 2-chloro-3 -methoxynaphthalene Example 15 Z-naphthalene sulfonyl bromide 2-bromonaphthalene Example 16 l-naphthalene sulfonyl fluoride l-fluoronaphthalene Example 17 1,6-naphthalene disulfonyl chloride 1,6-dichloronaphthalene Example 18 6-chl-oro-1,3-naphthalene disulfonyl chloride 1,3,6-trichloronaphthalene Example 19 4-nitro-1,5-naphthalene disulfonyl chloride 1,5 i icl1loro-4-nitronaphthalene Example 20 I (a) 1,3,7-naphthalene trisulfonyl chloride (b) 1,3,7-trichloronaphthalene Ya Xn wherein a is an integer from 0 to 3, n is an integer from 1 to 3, X is halogen, and Y is selected from the group consisting of halogen, nitr-o, lower alkyl and lower alkoxy, which comprises contacting, at a temperature of from about 30 C. to about C., a naphthalene sulfonyl halide of the formula,

with a sulfuryl halide of the formula SOzZz wherein a, n, X and Y have the same meaning as above, and wherein Z represents the same halogen as X, in the presence of a material selected from the group consisting of peroxides and hydroperoxides, the amount of sulfuryl halide employed per mol of naphthalene sulfonyl halide being up to 0.3 mol per sulfonyl halide group.

2. A process as defined in claim 1 wherein said naphthalene sulfonyl halide is a naphthalene disulfonyl halide.

3. A process as defined in claim 1 wherein a is zero. 4. A process as defined in claim 1 wherein said material is benzoyl peroxide.

5. A process as defined in claim 1 wherein X and Z have an atomic number of up to 35.

References Cited by the Examiner UNITED STATES PATENTS 1,183,094 5/1916 Mann et al. 2,852,565 9/1958 Nozaki 260-651 X 3,230,268 1/ 1966 Kobayashi et al 260-651 v FOREIGN PATENTS 98,433 12/ 1966 Germany.

13,971 9/1962 Japan.

OTHER REFERENCES Kroepelin et al.: Ang Chemie, vol. 64 (1952), pp. 273-274.

Gilman: Organic Chemistry, vol. I, p. 900 (1958). Groggins: Unit Processes in Organic Synthesis, 4th ed. (1952), p. 227.

LEON ZITVER, Primary Examiner.

JOHNSON, K. V. ROCKEY, Assistant Examiners, 

1. A PROCESS FOR PREPARING A COMPOUND OF THE FORMULA, 